Toluene Tolerated Li 9.88 GeP 1.96 Sb 0.04 S 11.88 Cl 0.12 Solid Electrolyte toward Ultrathin Membranes for All-Solid-State Lithium Batteries.

Sulfide solid electrolyte membranes employed in all-solid-state lithium batteries generally show high thickness and poor chemical stability, which limit the cell-level energy density and cycle life. In this work, Li 9.88 GeP 1.96 Sb 0.04 S 11.88 Cl 0.12 solid electrolyte is synthesized with Sb, Cl partial substitution of P, S, possessing excellent toluene tolerance and stability to lithium. The formed SbS 4 3- group in Li 9.88 GeP 1.96 Sb 0.04 S 11.88 Cl 0.12 exhibits low adsorption energy and reactivity for toluene molecules, confirmed by first-principles density functional theory calculation. Using toluene as the solvent, ultrathin Li 9.88 GeP 1.96 Sb 0.04 S 11.88 Cl 0.12 membranes with adjustable thicknesses can be well prepared by the wet coating method, and an 8 μm thick membrane exhibits an ionic conductivity of 1.9 mS cm -1 with ultrahigh ionic conductance of 1860 mS and ultralow areal resistance of 0.68 Ω cm -2 at 25 °C. The obtained LiCoO 2 |Li 9.88 GeP 1.96 Sb 0.04 S 11.88 Cl 0.12 membrane|Li all-solid-state lithium battery shows an initial reversible capacity of 125.6 mAh g -1 with a capacity retention of 86.3% after 250 cycles at 0.1 C under 60 °C.